Refrigerator control device



June 20, 1944. E w HQTTENRQTH, JR 2,351,968

REFRIGERATOR CONTROL DEVICE Filed Sept. 5, 1942 InVentow: Frederick WHottenr'oth Jr,

(5 is Abtorng Patented June 20, 1944 REFRIGERATOR CONTROL DEVICEFrederick W. Hottenroth, Jr., Schenectady, N. Y.,

assignor to General Electric Company, a. corporation of New YorkApplication September 5, 1942, Serial No. 457,413 I 17 Claims.

My invention relates to refrigerator control apparatus and particularlyto temperature responsive refrigerator control switches having manuallyoperable means for temporarily modifying the operation of the switchselectably to effect defrosting or quick-freezing operation thereof. Theinvention also contemplates automatic disabling of the modifying meansafter the desired abnormal control operation has been completed.

Accordingly, it is an object of my invention to provide a new-andimproved refrigerator control switch which is reliable and eificient inoperation and simple and inexpensive to manufacture.

It is a further object of my invention to provide a refrigerator controlapparatus having push button control means for modifying the normaloperation of the switch selectably to effect quickfreezing or defrostingoperation at temperatures beyond the normal operating range of theapparatus.

Another object of my invention is to provide a refrigerator controlswitch having magnetic control means for modifying the normal operationof the switch to effect either quick-freezing or defrosting operation.

It is a still further object of my invention to provide a refrigeratorcontrol switch having push button controlled magnetic means formodifying the normal operation of the switch selectably to effectquick-freezing or defrosting operation and arranged automatically toreturn the switch to its normal mode of operation after the abnormalcycle of operation has been completed.

According to my invention I provide a resiliently mounted switch memberarranged for substantially pivotal movement to a contact-closingposition by a thermally expansible bellows against the force of aloading spring arranged 'to' maintain following engagement between thebellows and the switch member and to move the switch member to acircuit-opening position upon operation of the control apparatus Iprovide man- 1 ually positionable magnetic means which is norimallybiased to an ineffective position and arranged for movement intoattractive relation with a magnetic portion of the switch memberpositively to attract the switch member to its circuit-opening position.The magnetic means applies to the switch member a releasable loadingforce which aids the loading spring in urging the switch member to itsopen-circuit position. I also provide magnetic means for modifying theoperation of the switch member in an opposite sense to effectquick-freezing operation of the control apparatus. This latter magneticmeans comprises a magnetic member fixedly mounted upon the base of thecontrol apparatus and a manually movable cooperating magnetic memberarranged when brought into attractive relation with the fixedly mountedmagnetic member to engage the switch member and positively move it toits circuit-closing position. By this latter arrangement a releasablemagnetic loading force is applied to the switch member in opposition tothe force of the loading spring so that the switch member remains in itscircuit-closing position for an abnormally long period.

For a more complete understanding of my invention and a furtherappreciation of its objects and advantages reference should now be hadto the following detailed description taken in conjunction with theaccompanying drawing in which Fig. l is a side elevation of arefrigerator control apparatus embodying my invention showing the devicewith the casing removed; and Fig. 2 is a sectional view of the apparatustaken along the lines 22 of Fig. 1 looking in the direction of thearrows.

Referring now to the drawing, the control apparatus comprises a switchmember If! resiliently and pivotally mounted at one end upon a base IIand carrying at its other end a movable contact l2. The base I I may beformed in any suitable manner, but as shown in the drawings it comprisesa U-shaped metallic portion forming a pair of supporting plates I3 andI4 disposed at parallel spaced relation and connected together at oneend in combination with a stationary contact block l5 of any suitableinsulating material which is positioned between the plates I3 and H attheir opposite ends.

The switch member ID comprises an irregularly shaped rigid magnetizableportion l6 which is carried at the free end of a cantilever spring stripHi, the other end of which is attached to abracket I1 forming part ofthe base II. The switch member In is controlled by an operating lever I9which extends in substantially parallel relation with the switch memberand passes through an aperture 20 in the spring l8 so that opposite endsof the lever I! extend parallel to the spring 18 and on opposite sidesthereof. One end of the lever l9 rests upon the bracket l1 and the otherend forms a movable seat for a loading sprin 25 which is positionedbetween the operating lever [B and the base H. The spring 25 is acompression spring and exerts a force upon the switch member Ill tendingto move the switch member to its circuit-opening position.

For moving the switch member to its circuitclosing position I provide athermally responsive expansible bellows 26 having one end fixedlymounted upon the upper base plate I3, as by bolts i311, and a movableend in engagement with an adjustable abutment on the spring l8.Specifically the movable end of th bellows 26 engages the end of athreaded shaft 21 which is adjustably mounted within an internallythreadedboss 28 in the operating lever l9 and carries at its other end agear 29. The interior of the bellows 26 is connected by a flexible tube3|). to a sealed bulb (not shown) which may be mounted in the space thetemperature of which is to be controlled. For example, it is well knownto those skilled in the art that such a bulb may suitably be mountedupon the evaporator of a refrigerator. The bellows 26, the flexible tube30 and the attached bulb form a closed space of variable volume whichmay be filled with any desired thermally expansible fluid. I prefer toutilize a non-volatile fluid so that the entire system is at all timescompletely filled with a thermally expansible liquid. Since the liquidis substantially incompressible, the position of the movable end of thebellows 26 will then be dependent solely upon the temperature of theexpansible fiuid in the system and independent of the magnitude of theloading force applied by the compression spring 25. i

In order to adjust the normal temperature to be maintained by my controlapparatus I provide means for adjusting the spacing between the switchmember H] and the movable end of the expansible bellows 26. As shown inthe drawings this adjustment comprises a spur gear 3| mounted upon ashaft 32 which is rotatably jour naled in the base Ii. The gear 3imeshes with the gear 29 and is arranged for manual rotation from a pointexterior of the casing. As shown, the end of the shaft 32 istransversely slotted at 33 and may be turned by any convenientinstrument, such as a screw-driver. If desired, the end of the shaft maybe provided with a rotatable knob for convenient direct manipulation.Thus, by turning the gear 31 the height of the abutment formed by theend of the threaded shaft 21 may be changed with respect to theinternally threaded lug 28 on the operating lever 19 and th spacingbetween the movable end of the expansible bellows 25 and the switchmember l may be varied.

The irregular shape of the rigid magnetizable portion l6 of the switchmember I0 is best shown at Fig. 2. From this view it will be observedthat the contact carrying end of the member 16 is ,L-shaped and providedwith an overhanging contact supporting plate 34 of suitable insulatingmaterial. The plate 34 is attached to the member l6 by any suitablemeans, such as a rivet 35. The movable contact l2 has a stem portionpassing through the plate 34, as shown at Fig. 1, and is carried by asmall wipe spring 36, the other end 75 of which is attached to the plate34. as by riveting at 31. The wipe spring 36 serves also as a currentconducting lead and is electrically connected to a line terminal on theinsulating base l5 by means of a flexible conductor 38.

For cooperation with the movable contact I2 I provide a fixed contact 39carried upon a small flat spring 40, one end of which is attached at 4|to the insulating base IS. The contact carrying end of the spring 40 maybe adjustably positioned by means of an adjusting bolt 42 mounted in thebas l5. To provide the switch member ID with a snap action there ispositioned adjacent the fixed contact 39 a small permanent magnet 45.The magnet 45 is fixedly attached to the base II as by a U-shaped strap46 and is aligned with that portion of the magnetizable member 16 lyingadjacent the contact l2. The member l5 serves as a keeper for thepermanent magnet 45 and provides the switch member ill with a snapaction in contact engaging and disengaging movements in a manner wellknown to those skilled in the art.

Since it is frequently desirable in a switch of this type to providemeans for manually moving the switch member to an off position andpositively precluding further control operation of the device untildesired, I have shown a push button 41 comprising a head portionexterior of the easing and a slidable plate 48 having a hooked endportion arranged to engage a cooperating hooked end portion 49 formed onthe member IS. The plate 48 passes through the base plate I3 and througha parallelly disposed supporting bracket 50 attached to the plate l3. Aflexibl spring strip 5| attached to the base plate 13 and frictionallyengaging the side of the slidable plate 48 serves to hold the plate 48frictionally in any a desired position.

My invention particularly contemplates the provision of manuallycontrollable magnetic means for modifying the normal cyclic operation ofthe control apparatus to effect quickfreezing or defrosting operation ofthe apparatus as desired. For this purpose I mount upon the switchmember I 0 a small permanent magnet which in the drawings is shownattached to the member l6 by a U-shaped clamping strap 56. Forcooperation with the magnet 55 to provide defrosting operation of thecontrol apparatus I have shown a small magnetizable keeper 5'! which ispreferably made of soft iron and is mounted upon the end of a slidablemanually operable push button 58. The push button 58 comprises a headportion exterior of the base plate l3 and a stem portion 59 passingthrough the plate I3 and bracket 50 and having a shoulder 60 positionedtherebetween. A compression spring SI surrounding the stem 59 betweenthe bracket 50 and the shoulder 60 serves to bias the push button 58 toa normal upper limiting position in which the keeper 51 engages thebracket 50 and is spaced from the permanent magnet 55 a sufficientdistance to insure that it is beyond the effective attractive range ofthe magnet. A flat spring 62 attached to the base plate 13 is arrangedto be engaged by the shoulder 60 and sen/e as a resilient lower limitstop for the push button 58.

To provide for temporarily modifying the operation of the switch memberIII for effecting quickfieezing operation of control apparatus I mount apermanent magnet 55 in fixed position upon the base plate i 4 by anysuitable means, such as a U-shaped clamping strap 66. A movable keeper61 for cooperation with the magnet 65 is carried by a manually operatedpush button 66 which, is slidably mounted in the base plate ii. The pushbutton 66 comprises a head portion and a shank portion 66 which extendsthrough suitable openings in the base plate I! and the bracket 66 andcarries at its lower end the magnetizable keeper 61. The push button 66is also similar to the push button 66 in that the shank portion thereofis provided with a shoulder 16 lying-between the plate l6 and thebracket 66 and providing an upper seat for a compression spring Hpositioned between the bracket 66 and the shoulder 66 to bias the pushbutton to its outermost position in which the keeper 61 acts as alimiting stop by engagement with the bracket 66. Referring now to Fig. 2it will be observed that the magnetizable portion I6 of the switchmember I6 is cut away at 12 to permit direct engagement of the keeper 6!with the magnet 66. The

- keeper 6! is provided with a lug I6 arranged to engage the switchmem-ber II! when the keeper moves into attractive relation with respectto the magnet 66. For the purpose of adjusting the position of theswitch member ill with respect to the keeper 61 an adjustable abutmentcomprising a bolt 16 is arranged on the portion l6 of the switch memberID for engagement with the lug I6 on the keeper 61. The keeper 61' isnormally p the stress of the spring l6 attains a predeterbiased to theposition shown at Fig. 1 so that in normal cyclic operation of theswitch member Hi the keeper 6! is beyond the range of movement of theswitch member and has no effect thereon. Since the magnetizable p'ortionl6 of the switch member I0 is cut away directly above the magnet 66,there is no appreciable influence-exerted upon the switch member by themagnet.

From the foregoing detailed description of the various parts of mycontrol apparatus and their relation with respect to each other, it isbelieved that the operation of the device as a whole will be clear fromthe following brief description.

To initiate operation of the device from the position shown at Fig. 1the push button 61 must first be depressed to set free the movable endof the switch member I 6. If it is assumed that after this is done theswitch member remains in the position shown at Fig. 1 it indicates thatthe fluid in the temperature responsive bellows 26 is contracted andthat the temperature of the controlled space is sufficiently low. If nowthe temperature of the space to be cooled increases, the bellows 26 willexpand and move the switch member ID into its circuit-closing positionagainst the force of the compression spring 26. In this movement thebellows 26 forces the operating lever I! to rotate about its point ofengagement with the bracket ll thereby to depress the extending end ofthe spring strip l6 which carries with it the magnetizable portion I6 ofthe switch member i0. As the portion I6 of the switch member approachesthe snap action magnet 66 the attractive force between the magnet 46 andthe switch member gradually increases to a point at which the switchmember is suddenly pulled into its circuit-closing positionindependently of the bellows 26 so that the contacts l2 and 36 engagewith a snap action. Closing of the circuit at the cbntacts l2 and 69initiates operation of a refrigerating apparatus (not shown) which coolsthe conditioned space and causes contraction of the fluid in the bellows26. As the bellows 26 contracts the operating lever 16 is held infollowing engagement with the movable end of the bellows by thecompression spring 26 so that the operating lever is gradmined value, itwill be sufficient to overcome the force of the snap action magnet 66and the ma net 46 will release the switch member II to permit it to moveto its circuit-opening position with a snap action. It will beunderstood that the foregoing opening and closing movement of the switchmember it! continues in a' cyclic manner to maintain the temperature ofthe space to be cooled within the limit of a predetermined normal range.The limits of this predetermined normal range may be adjusted bymanipulation of the shaft 66 to adjust the spacing between the operatinglever l6 and the movable end of the bellows 26.

If it is desired to obtain defrosting operation of the control apparatusthe push button 66 is depressed until the keeper 61 engages thepermanent magnet 66. If this operation is carried out with the switchmember ID in its open-circuit position the shoulder 66 of'the pushbutton 66 will be brought into engagement with the stop spring 62 whichresiliently resists further downward movement of the push button 66 andits keeper 61. If the switch member I6 is in its circuit-closingposition when the push button 66 is depressed, the shoulder 66 deformsthe spring 62 as the push button is manually moved until it engages themagnet 66, and upon release of the push button the spring 62 returns tosubstantially its normal shape and in so doing it partially returns thepush button 66 and positively moves the switch member III to itscircuitopening position. When the keeper 6! is in engagement with themagnet 66 there is applied to the switch member a releasable magneticloading force which aids the loading spring 26 in resistingcircuit-closing movements of the switch member Ill. The switch memberwill now fail toclose the contacts i2 and 66 when the temperature of theconditioned space reaches the upper limit of its normal range because,although due to the incompressibility of the liquid in the bellows 26the operating lever l9 has been depressed to its circuit-closingposition, the magnetic attraction between the magnet 66 and its keeper6'! deforms the cantilever spring l6 and prevents circuit-closingmovement of the magnetizable portion l6 of the switch member.Consequently, the temperature of the conditioned space continues to riseso that the operating lever is Further depressed and the spring I8 isfurther deformed. When the deformation of the spring l6 reaches apredetermined point its bias will be sufllcient to overcome theattractive force between the magnet 66 and its keeper 6] so that theportion l6 of the switch member l6 will be released with a snap actionand will move quickly to its circuit-closing position in which it isattracted by the snaplaction magnet ,66. As soon as the keeper 6'!releases the magnet 66 the compression spring 6| returns the push button66v to its normal inactive position shown at Fig. l. The spring 6|,therefore, effects automatic disabling of .the defrosting adjustment assoon as a single defrosting cycle has been completed. It will beunderstood that while such a spring is desirable it is also possible toprovide apparatus in which the push button 66 remain in its de+ pressedposition after it releases the magnet 66,

so that upon return of the switch member W to its,

and another defrosting cycle will be initiated. In such a casediscontinuance of the defrosting operation could be accomplished only bymanual withdrawal of the push button 58.

It now it is desired to effect quick-freezing operation of the controlapparatus the push button 6| may be depressed until the keeper 81engages its cooperating permanent magnet 65. If this operation iscarried when the switch member ID is in its closed-circuit position thelug 13 will simply be brought into the path of movement of the abutmentH. Ii, on the other hand, the push button 88 is depressed when theswitch member I is in its circuit-opening posiiton the lug 13 willengage the abutment 14 and positively carry the portion l6 of the switchmember ID to its circuit-closing position. It will be evident that theattractive force between the permanent magnet 65 and its keeper 61applies to the portion I8 01' the switch member I 0 a magnetic loadingforce opposing the force of the loading spring 25 and aiding the snapaction magnet 45. Thus, when the temperature of the space to be cooledreaches the lower limit of its normal range the operating lever l9 willbe in its normal circuitopening position due to the incompressibility ofthe liquid in the bellows 26, but the portion 15 of the switch member Inwill be retained in its circuit-closing position against the bias of thecantilever spring l8 due to the force of attraction between the magnet65 and its keeper 61. As the temperature of the conditioned spacedecreases below the lower limit of its normal range the bellows 26further collapses and the operating lever I9 is further rotated in aclockwise direction as viewed in the drawing so that the cantileverspring I8 is additionally stressed. When the stress of the spring l8reaches a predetermined point it will be sufficient to overcome theforce of attraction of the magnet 65 for its keeper 6'! and the magnet45 for the member l6 so that the portion l6 of the switch member ID willmove upwardly and will force the keeper 61 out of engagement with themagnet 65. As soon as the keeper 6! is released by the magnet thecompression spring Tl will move the push button 68 and its attachedkeeper 6'! to the normal position shown at Fig. 1, thereby to releasethe switch member and permit it to move with a snap action to itscircuit-opening position shown in the drawing.

While I have shown only a single embodiment of my invention by way ofillustration many further modifications will occur to those in the art.I therefore wish to have it understood that by the appended claims Iwish to cover all such modifications as fall within the true spirit andscope of my invention.

What I claim as new and desired to secure by Letters Patent of theUnited States is:

1. In a refrigerator control apparatus for controlling the temperatureof a space to be cooled, a switch member movable between circuit-openingand circuit-closing positions to control said temperature, expansiblemeans responsive to said temperature for effecting cyclic operation ofsaid switch member between said positions normally to maintain saidtemperature within a predetermined range, a pair of permanent magnetsoperatively associated with said switch member, a first ature above saidpredetermined range, and a second magnetizable member normally spacedfrom the other of said magnets and movable into attractive relationtherewith releasably to bias said switch member to a circuit-closingposition thereby temporarily to maintain said space at a temperaturebelow said predetermined range.

2. In a refrigerator control apparatus for controlling the temperature01' a space to be cooled, a switch member movable betweencircuit-opening and circuit-closing positions to control saidtemperature, expansible means responsive to said temperature foreffecting cyclic operation of said switch member between said positionsnormally to maintain said temperature within a predetermined range, apermanent magnet operatively associated with said switch member, and amagnetizable member biased to a position normally spaced from saidmagnet and movable into attractive relation therewith releasably toretain said switch member in a circuit-opening position therebytemporarily to maintain said space at a temperature above saidpredetermined range.

3. In a refrigerator control apparatus for controlling the temperatureof a space to be cooled, a switch member movable between circuit-openingand circuit-closing positions to control said temperature, expansiblemeans responsive to the temperature of said space for eilecting cyclicop-- eration of said switch member between said positions normally tomaintain said temperature within a predetermined range, a permanentmagnet operatively associated with said switch member, and amagnetizable member biased to a pomagnetizable member normally spacedfrom one of said magnets and movable into attractive re- -lationtherewith releasably to bias said switch member to a circuit-openingposition thereby temporarily to maintain said space at a tempersitionnormally spaced from said magnet and movable into attractive relationwith said magnet releasably to retain said switch member in acircuit-closing position thereby temporarily to maintain said space at atemperature below said predetermined range.

4. In a refrigerator control apparatus for controlling the temperatureof a space to be cooled, a pivoted switch member movable betweencircuit-opening and circuit-closing positions to control saidtemperature, said switch member including a magnetic portion, means forbiasing said switch member to said circuit-opening position, anexpansible bellows having a portion movable in response to saidtemperature to move said switch member to said circuit-closing positionthereby to effect cyclic operation of said switch member normally tomaintain said temperature within a predetermined range, magnetic meansmounted for limited movement and normally positioned in spaced relationto said magnetic portion of said switch member, said magnetic meansbeing movable into attractive relation with said magnetic portion ofsaid switch member thereby releasably to retain said switch member inone of said circuit-controlling positions for an abnormal period so thatsaid space temporarily assumes a temperature beyond said predeterminedrange.

5. In a refrigerator control apparatus for controlling the temperatureof a space to be cooled, a base, a switch member pivotally mounted uponsaid base and movable between circuit-opening and circuit-closingpositions to control said temperature, means for biasing said switchmember to said circuit-opening position, an expansible bellows having aportion movable in response to said temperature to move said switchmember to said circuit-closing position thereby to effect cyclicoperation of said switch member and normally to maintain saidtemperature within a predetermined range, a first magnetic memberfixedly mounted upon said base in spaced relation to said switch member,and a second magnetic member normally spaced from said first magneticmember and movable into attractive relation therewith, said secondmagnetic member being arranged to engage said switch member when movedinto attractive relation with said first magnetic member and releasablyto retain said switch member in one of said circuit-controllingpositions for an abnormal period so that said space temporarily assumesa temperature beyond said predetermined range.

6. In a refrigerator control apparatus for controlling the temperatureof a space to be cooled, a base, a switch member pivotally mounted uponsaid base for movement between circuit-opening and circuit-closingpositions, a spring for biasing said switch member to saidcircuit-opening position, a fiuid filled bellows expansibleand'contractible in response to the temperature of said space to movesaid switch member to said circuitclosing position in opposition to thebias of said spring thereby normally to maintain said temperature withina predetermined normal range, a permanent magnet mounted upon saidswitch member, a magnetizable keeper operatively associated with saidpermanent magnet, said keeper being normally positioned beyond theefiective attractive range of said permanent magnet, and manual meansfor moving said keeper to a second position in attractive relation withsaid permanent magnet thereby to apply to said switch member an abnormalbiasing force toward one of its circuit-controlling positions so thatsaid space temporarily assumes-a temperature beyond said normal range. I

7. In a refrigerator control apparatus for controlling the temperatureof a space to be cooled, a. base, a switch member pivotally mounted uponsaid base and movable between circuit-opening and circuit-closingpositions to control said temperature, means for biasing said switchmember to said circuit-opening position, an expansible bellows having aportion movable in response'to said temperature to move said switchmember to said circuit-closing position thereby to effect cyclicoperation of said switch member and normally to maintain saidtemperature within a predetermined range, a permanent magnet fixedlymounted upon said base, a movable keeper for said magnet normally spacedfrom said magnet and having a portion positioned to engage said switchmember positively to move said switch switch member movable betweencircuit-opening and circuit-closing positions, magnetic means arrangedto provide movement of said switch member between said positions with asnap action, temperature responsive means for moving said switch memberto said circuit-closing position, a loading springfengaging said switchmember to oppose said temperature responsive means and to bias saidswitch member to said circuit-opening position, a permanent magnetmounted upon said switch member, a movable keeper for said permanentmagnet biased to a normal position beyond the effective attractive rangeof said magnet, and a manually operable push button for moving saidkeeper into attractive relation with said magnet, said keeper beingarranged to attract said switch member to said circuit-opening positionand releasably to oppose movement of said switch member to saidcircuit-closing position thereby to eiTect a condition of defrostingoperation of said control device.

9. A refrigerator control device comprising a switch member movablebetween circuit-opening and circuit-closing positions, magnetic meansarranged to provide movement of said switch member between saidpositions with a snap action, temperature responsive means for movingsaid switch member to said circuit-closing position, a loading springengaging said switch member to oppose said temperature responsive meansand to bias said switch member to said circuitopening position, apermanent magnet mounted upon said base, a movable keeper operable inconjunction with said permanent magnet and biased to a. normal positionbeyondthe effective attractive range of said magnet, a manually operablepush button for moving said keeper into attractive engagement withsaid'magnet, and a lug carried by said keeper and arranged for movementinto the path of movement of said switch member positively to move saidswitch member to said circuit-closing position, whereby the attractiveforce between said magnet and said keeper releasably opposes movement ofsaid switch member to said circuit-opening position to effect acondition of quick-freezing operation of said control device.

10. A refrigerator control device comprising a space, a magnetic switchmember movable between circuit-opening andcircuit-closing positions, amagnetic means mounted upon said base and operable in conjunction withsaid'switch member to provide said switch member with a snap action,temperature responsive means for moving said switch member to saidcircuit-closing position, a loading spring engaging said switch memberto oppose said temperature responsive means and to bias said switchmember to said circuit-opening position, first movable magnetic meansbiased to a normal position spaced from said magnetic switch member, amanually operable push button for moving said movable magnetic meansinto attractive relation with said switch member, said movable magneticmeans being arranged to attract said switch member to saidcircuit-opening position and releasably to oppose movement of saidswitch member to said circuit-closing position thereby to effect acondition of defrosting operation of said control device, a fixedmagnetic member mounted upon said base in spaced relation to said switchmember, and second movable magnetic means operable in conjunction withsaid fixed magnetic member and biased to a normal position beyond theeffective attractive range of said member, a second manually operablepush buttonofor moving said second movable magnetic means intoattractive engagement with said fixed magnetic member, and a lu movablewith said second movable magnetic means into the path of movement ofsaid switch member, said keeper and lug being arranged positively tomove said switch member to said circuit-closing position and releasablyto oppose movement of said switch member to said circuit-openingposition thereby to effect a condition of quick-freezing operation ofsaid control device.

11. A refrigerator control device comprising a switch member movablebetween circuit-opening and circuit-closing positions, a thermallyresponsive expansible bellows for moving said switch member to saidcircuit-closing position, a loading spring engaging said switch memberto oppose said expansible bellows and to move said switch member to saidcircuit-opening position, magnetic means manually movable intoengagement with said switch member positively to move said switch memberto said circuit-closing position and releasably to oppose said loadingspring thereby to effect quick-freezing operation of said controldevice, and second magnetic means manually movable into engagement withsaid switch member positively to move said switch member to saidcircuit-opening position and releasably to oppose said expansiblebellows thereby to effect defrosting operation of said control device.

12. A refrigerator control device comprising a base, a switch membermounted upon said base for movement between circuit-opening andcircuit-closing positions, a thermally expansible bellows for movingsaid switch member to said circuit-closing position, a loading springengaging said switch member to oppose said thermally expansible bellowsand to move said switch member to said circuit-opening position,manually adjustable means for varying the bias upon said loading springthereby to select a normal operating range for said control device,magnetic means mounted upon switch member, a first manually movablemagnetic member normally biased to a position spaced from said magneticmeans and movable into attractive engagement therewith to bias saidswitch member to said circuit-opening position and releasably to aidsaid loading spring thereby to effect defrosting operation of saidcontrol device, magnetic means mounted upon said base, and a secondmanually movable magnetic member normally biased to a position beyondthe effective range of second magnetic means and movable into attractiveengagement therewith, said second movable magnetic member being providedwith means engaging said movable switch member positively to move saidswitch member to said circuit-closing position and releasably to opposesaid loading spring thereby to eflect quick-freezing operation of saidcontrol device.

13. A refrigerator control apparatus comprising a base, a switch membermounted for movement between circuit-opening and circuit-closingpositions, said switch member comprising a cantilever spring attached atone end to said base and carrying at its other end a rigid magnetizablemember, a liquid-filled thermally expanslble bellows engaging saidspring intermediate its ends to move said switch member to saidcircuit-closing position, a loading spring for maintaining followingengagement between said switch member and said bellows and moving saidswitch member to its circuit-opening position thereby to effect cyclicoperation of said switch member in response to temperatures within apredetermined normal range, and magnetic means movable into engagementwith said rigid magnetizable portion of said switch member and arrangedto apply to said switch member a releasable magnetic loading forcethereby temporarily to maintain a temperature beyond said predeterminednormal range.

14. A refrigerator control apparatus comprising a base, a switch membermounted for movement between circuit-closing and circuit-openingpositions, said switch member comprising a cantilever spring attached atone end to said base and carrying at its other end a rigid magnetizabiemember, a liquid-filled thermally expansible bellows engaging saidspring intermediate its ends to move said switch member to saidcircuitclosing position, a loading spring for maintaining followingengagement between said switch member and said bellows and moving saidswitch member to said circuit-opening position thereby to eiiect cyclicoperation of said switch member in response to temperatures within apredetermined normal range, an adjustable abutment on said switch memberfor varying the relation of said switch member to said bellows therebyto adjust the limits of said normal range, and magnetic means normallybiased to an ineffective position and manually movable into engagementwith said magnetizable portion of said switch member to apply to saidportion a releasable magnetic loading force thereby temporarily tomaintain a temperature beyond said normal range.

15. A refrigerator control apparatus comprising a base, a switch membermounted for movement between circuit-opening and circuit-closingpositions, said switch member comprising a rigid magnetizable portionattached at one end of said base by a cantilever spring, a snap actionmagnet operable in conjunction with said rigid magnetizable portion ofsaid switch member, an adjustable abutment mounted upon said cantileverspring intermediate its ends, a liquid-filled temperature responsiveexpansible bellows engaging said abutment to move said switch member tosaid circuit-closing position, a loading spring for maintainingfollowing engagement between said adjustable abutment and said bellowsand moving said switch member to said circuit-opening position therebyto provide cyclic operation of said switch member in response totemperatures within a predetermined normal range, manually operablemeans for adjusting the position of said abutment to vary the spacingbetween said abutment and said bellows thereby to select upper and lowerlimits of said normal range, a pair of permanent magnets operativelyassociated with said switch member, a first magnetizable member biasedto a normal position spaced from one of said magnets and movable intoattractive relation therewith releasably to bias said rigid portion ofsaid switch member to a circuit-opening position and thereby temporarilyto maintain a temperature above said normal range, and a secondmagnetizable member biased to a normal position spaced from the other ofsaid magnets and movable into attractive relation therewith releasablyto bias said switch member to a circuit-closing position and therebytemporarily to maintain a temperature below said predetermined normalrange.

16. A refrigerator control apparatus comprising a base, a switch membermounted upon said base for movement between'circuit-opening andcircuit-closing positions, said switch member comprising a rigidmagnetizable portion and a cantilever spring pivotally connecting saidrigid portion to said base, a liquid-filled expansible bellows engagingsaid cantilever spring intermediate its ends to move said switch memberto said circuit-closing position, a loading spring for maintainingfollowing engagement between said bellows and said spring and movingsaid switch member to said circuit-opening position thereby to effectcyclic operation of said switch member in response to temperatureswithin a predetermined normal range, and magnetic means manuallypositionable to engage said rigid portion of said switch member in oneof its circuit-controlling positions, said magnetic means applying tosaid rigid portion of said switch member a releasable loading forceproducing deformation of said cantilever spring prior to movement ofsaid switch member to the other of said circuit-controlling positionswhile said bellows moves beyond its normal limits of movement, wherebysaid temperature is permitted temporarily to assume a value without saidpredetermined range.

1'7. In a refrigerator control apparatus for controlling the temperatureof the space to be cooled, a switch member movable betweencircuit-opening and circuit-closing positions to control saidtemperature, means responsive to said temperature ior effecting cyclicoperation of said switch member between said positions normally tomaintain said temperature within a predetermined range, a pair ofmagnetic members including a permanent magnet operatively associatedwith said switch member, one of said magnetic members being mounted uponsaid switch member and the other of said magnetic members being movablymounted with respect thereto and normally biased to a position out ofattractive relation with said one member, said movably mounted magneticmember being movable into attractive relation with said one magneticmember releasably to retain said switch member in a predeterminedcircuit controlling position thereby temporarily to maintain said spaceat a temperature beyond said predetermined range.

FREDERICK W HO'I'IENRO'I'H, JR.

